title: Two-dimensional ³¹P,¹H NMR spectroscopic profiling of phospholipids in cheese and fish.
abstract: Phospholipids (PLs) comprise an important lipid class in food because of their technological use as emulsifiers and their nutritional value. This study used one-dimensional (31)P NMR and two-dimensional (2D) (31)P,(1)H COSY NMR spectroscopy for the determination of the PL composition of cheese and fish after liquid-liquid enrichment. This extraction step enabled the identification of 10 PLs in cheese and 9 PLs in fish by 2D (31)P,(1)H NMR. Variations in the (31)P shifts indicated differences in the fatty acids attached to the individual PLs. The total PL content in cheese fat and fish oil ranged from 0.3 to 0.4% and from 5 to 12%, respectively. Phosphatidylcholine was the most prominent PL in both matrices (up to 65%). Minor PLs (limit of detection = 4 nmol, i.e. 500 μL of an 8 μM solution) were identified in forms of phosphatidic acid, lysophosphatidic acid, and phosphatidylglycerol. Specific cross couplings and (1)H fine structures in the 2D (31)P,(1)H NMR spectra proved to be valuable for the assignment and verification of known and uncommon PLs in the samples.
authors.affiliation: Department of Food Chemistry, Institute of Food Chemistry, University of Hohenheim , Garbenstrasse 28, D-70599 Stuttgart, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Kaffarnik
authors.forename: Ina
authors.initials: I
authors.lastname: Ehlers
authors.forename: Gerhard
authors.initials: G
authors.lastname: Gröbner
authors.forename: Jürgen
authors.initials: J
authors.lastname: Schleucher
authors.forename: Walter
authors.initials: W
authors.lastname: Vetter
mesh_terms: D002611:Cheese / Q000032:analysis*; D005227:Fatty Acids / Q000032:analysis; D005396:Fish Products / Q000032:analysis*; D005504:Food Analysis / Q000379:methods*; D057230:Limit of Detection; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010713:Phosphatidylcholines / Q000032:analysis; D010743:Phospholipids / Q000032:analysis*; D010758:Phosphorus
chemical_list: D005227:Fatty Acids; D010713:Phosphatidylcholines; D010743:Phospholipids; D010758:Phosphorus